Conventional methods of quantitative mass analysis using ion trap mass spectrometers require the analyte and corresponding internal standard ions to be injected and analyzed from two time-separated ion injection events. Any fluctuations in the ionization process which occur in between those two ion injection events introduces inaccuracy in the quantitative mass analysis and subsequently leads to a bigger relative standard deviation (RSD) and therefore uncertainty in the measurement.
What is needed is a quantitative mass analysis method that minimizes or eliminates errors introduced by the fluctuations in the ionization process and improves the accuracy in the measurement.